p {
  margin: 0;
  margin-bottom: 10px;
}
button {
  cursor: pointer;
}

.grandfather {
  max-width: 600px;
  margin: 60px auto 0;
  border: 1px solid #cccccc;
  padding: 20px;
}
.container {
  display: flex;
}
.box {
  padding: 20px;
  width: calc(50% - 10px);
  border: 1px solid blue;
}
.box:first-child {
  margin-right: 20px;
}
.child {
  min-height: 60px;
  padding: 20px;
  border: 1px solid #f56c6c;
}
.child:nth-child(3) {
  margin-bottom: 20px;
}
